A sandwich component should be generally understood as meaning a component that is made up of layers of the same material or different materials. In the simplest case, sandwich components consist of two cover layers, an upper cover layer and a lower cover layer, as well as a core layer, which is arranged between the upper cover layer and the lower cover layer. The cover layers are configured in the manner of fibres and/or woven fabrics and may be penetrated by an adhesive-like matrix material. An ultimate connection between the individual layers usually takes place by pressing by way of a suitable tool, such as for example a press.
Such sandwich components are used in many different areas. In recent years, however, their importance particularly as a structural component in the area of lightweight automotive construction has increased enormously.
The prior art discloses many different approaches to the production of structural components.
In order for a durable connection between the upper and lower cover layers and the core layer to be achieved, matrices, in particular adhesive-type resins, are used which during pressing of the cover layers and the core layer are squeezed through the cover layers and in this way produce a connection between the cover layers and the core layer. The application of the matrix material here is performed only from the outside onto the outermost cover layer. Typically, an excessive amount of matrix material is applied here, in order to ensure reliable penetration of the cover layers with matrix material when the individual layers are pressed.
In the manufacture of a sandwich component according to a method which has been briefly described above the disadvantage arises that only one type of matrix material (in terms of composition and application thickness) may be applied onto the outermost cover layer. Moreover, depending on the viscosity of the matrix material and the permeability of the cover layer, the matrix material may ingress too deeply into the core layer and penetrate the core layer in an unchecked manner. In order to prevent this, according to the prior art a barrier layer which is impermeable to the matrix material is often disposed between the cover layer and the core layer. However, this barrier layer in most cases has to be adhesively bonded to the core layer in a separate operational procedure.